scholarly journals Biocontrol potential of Bacillus thuringiensis isolated from soil samples against mosquito larvae

2018 ◽  
Vol 20 (2) ◽  
pp. 279
Author(s):  
I.A. Adeyemo ◽  
S.O. Abdul-Wahab ◽  
A.A. Obadofin
Keyword(s):  
Bacillus Thuringiensis ◽  
Soil Samples ◽  
Mosquito Larvae ◽  
Biocontrol Potential

PCR-Based Identification of Bacillus thuringiensis Isolated from Soil Samples in Nigeria

2000 ◽  
Vol 55 (11-12) ◽  
pp. 987-990 ◽  
Author(s):  
Abiodun A. Ogunjimi ◽  
George O. Gbenle ◽  
Daniel K. lukoya ◽  
Ezekiel O. Akinrimisi
Keyword(s):  
Bacillus Thuringiensis ◽  
Pcr Amplification ◽  
Soil Samples ◽  
Crystal Protein ◽  
Mosquito Larvae ◽  
Total Dna ◽  
Target Sequences ◽  
Crystal Protein Genes

Six isolates of Bacillus thuringiensis isolated from soil samples confirmed to be toxic to mosquito larvae were differentiated using a PCR-Based technique. Three of these isolates initially identified using a serological technique were further differentiated with the PCR amplification of the δ-endotoxin target sequences. Using the total DNA of isolates as tem plate, at least four isolates yielded amplicons one or all the crystal protein genes, cryl a, b, c, or II with sizes ranging from 238-1070 bp. None of these isolates yielded an amplicon for any of Cry IV A, B and D tested. Of the four isolates identified by PCR technique one isolate remained unidentified by serology.

scholarly journals Different Hatching Rates of Floodwater Mosquitoes Aedes sticticus, Aedes rossicus and Aedes cinereus from Different Flooded Environments

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 279
Author(s):  
Anders Lindström ◽  
Disa Eklöf ◽  
Tobias Lilja
Keyword(s):  
Tap Water ◽  
Soil Samples ◽  
Mosquito Larvae ◽  
Retaining Structures ◽  
Retaining Structure ◽  
Large Numbers ◽  
Random Samples ◽  
Nuisance Species ◽  
Flooding Events ◽  
Hatching Rates

In the lower Dalälven region, floodwater mosquitoes cause recurring problems. The main nuisance species is Aedes (Ochlerotatus) sticticus, but large numbers of Aedes (Aedes) rossicus and Aedes (Aedes) cinereus also hatch during flooding events. To increase understanding of which environments in the area give rise to mosquito nuisance, soil samples were taken from 20 locations from four environmental categories: grazed meadows, mowed meadows, unkept open grassland areas and forest areas. In each location 20 soil samples were taken, 10 from random locations and 10 from moisture retaining structures, such as tussocks, shrubs, piles of leaves, logs, and roots. The soil samples were soaked with tap water in the lab, and mosquito larvae were collected and allowed to develop to adult mosquitoes for species identification. Fewer larvae hatched from mowed areas and more larvae hatched from moisture retaining structure samples than random samples. The results showed that Aedes cinereus mostly hatch from grazed and unkept areas and hatched as much from random samples as from structures, whereas Aedes sticticus and Aedes rossicus hatched from open unkept and forest areas and hatch significantly more from structure samples. When the moisture retaining structures in open unkept areas where Aedes sticticus hatched were identified it was clear that they hatched predominantly from willow shrubs that offered shade. The results suggest that Ae. sticticus and Ae. cinereus favor different flooded environments for oviposition.

scholarly journals Distribution of Bacillus thuringiensis subsp. israelensis in Soil of a Swiss Wetland Reserve after 22 Years of Mosquito Control

2011 ◽  
Vol 77 (11) ◽  
pp. 3663-3668 ◽  
Author(s):  
Valeria Guidi ◽  
Nicola Patocchi ◽  
Peter Lüthy ◽  
Mauro Tonolla
Keyword(s):  
Spatial Distribution ◽  
Bacillus Thuringiensis ◽  
Confidence Interval ◽  
Quantitative Pcr ◽  
Mosquito Control ◽  
Soil Samples ◽  
Sampling Point ◽  
Content Type ◽  
Large Numbers ◽  
Continuous Accumulation

ABSTRACTRecurrent treatments withBacillus thuringiensissubsp.israelensisare required to control the floodwater mosquitoAedes vexansthat breeds in large numbers in the wetlands of the Bolle di Magadino Reserve in Canton Ticino, Switzerland. Interventions have been carried out since 1988. In the present study, the spatial distribution of restingB. thuringiensissubsp.israelensisspores in the soil was measured. TheB. thuringiensissubsp.israelensisconcentration was determined in soil samples collected along six transects covering different elevations within the periodically flooded zones. A total of 258 samples were processed and analyzed by quantitative PCR that targeted an identical fragment of 159 bp for theB. thuringiensissubsp.israelensis cry4Aaandcry4Bagenes.B. thuringiensissubsp.israelensisspores were found to persist in soils of the wetland reserve at concentrations of up to 6.8 log per gram of soil. Continuous accumulation due to regular treatments could be excluded, as the decrease in spores amounted to 95.8% (95% confidence interval, 93.9 to 97.7%). The distribution of spores was correlated to the number ofB. thuringiensissubsp.israelensistreatments, the elevation of the sampling point, and the duration of the flooding periods. The number ofB. thuringiensissubsp.israelensistreatments was the major factor influencing the distribution of spores in the different topographic zones (P< 0.0001). These findings indicated thatB. thuringiensissubsp.israelensisspores are rather immobile after their introduction into the environment.

scholarly journals Effects of two formulations based on Bacillus thuringiensis subsp. israelensis on Aedes aegypti mosquito larvae under laboratory conditions

2008 ◽  
Vol 23 (4) ◽  
pp. 251-258
Author(s):  
Milenka Peric ◽  
Mirjana Prijovic ◽  
Goran Andric
Keyword(s):  
Bacillus Thuringiensis ◽  
Aedes Aegypti ◽  
Aqueous Suspension ◽  
Pure Water ◽  
Clay Content ◽  
Experimental Period ◽  
Mosquito Larvae ◽  
Water Dispersible ◽  
Bacillus Thuringiensis Subsp ◽  
Zero Time

Toxicity and persistence of two formulations based on Bacillus thuringiensis subsp. israelensis applied to Aedes aegypti mosquito larvae were tested under laborabory conditions. The formulations were: a) water dispersible granules (product VectoBac WDG), and b) aqueous suspension (product VectoBac 12AS). The effects of both products on mosquito larvae were tested immediately after their dilution in pure water (zero time) and in 1-, 2-, 8- and 13-day old solutions. The two products were also tested in mixtures of water and clay at a rate of 0.5 g clay/150 ml water immediately after product dilution, and in one-day old solutions containing 0.1 and 0.05 g of clay in the same amount of water. The product VectoBac WDG was persistent and highly effective against Ae. aegypti larvae in pure water after the longest experimental period of 13 days, and significantly more effective than VectoBac 12AS at equal rates of application. The effectiveness of VectoBac 12AS weakened significantly after 8 and 13 days of treatment, compared to the effects at zero time and in 1- and 2-day old solutions. High clay content in water significantly reduced the larvicidal effectiveness of both products, indicating its possible compromising role during product application in practice.

Friendly Foes: The Bio-control Agents

2018 ◽  
Vol 2 (01) ◽  
Author(s):  
Kalpana Singh
Keyword(s):  
United States ◽  
Biological Control ◽  
Bacillus Thuringiensis ◽  
United States Of America ◽  
Control Agent ◽  
Mosquito Larvae ◽  
Bt Cotton ◽  
Economic Threshold ◽  
Pest Population ◽  
Natural Way

The bio-control agents are those organisms that manage the pest population in natural way and keep them below the economic threshold and are thus applied by the agency of man. This process is known as bio-control or biological control. They are foes to the pests and are thus beneficial and a friend for us. There are many pathogens (Bacillus thuringiensis, Bt cotton), parasites (parasitoids, ex. Parasitic wasps, tachinid flies) and predators (ex. Gambusia fish against mosquito larvae) that can be applied as bio-control agents. Many are being used as effective pest control agent in Europe and United States of America. There is lots of potential in this field and more explorations and researches need to be done in an agricultural country like India.

scholarly journals Strong mosquitocidal Bacillus thuringiensis from Mt. Everest

Our Nature ◽  
1970 ◽  
Vol 5 (1) ◽  
pp. 67-69
Author(s):  
Upendra Thapa Shrestha ◽  
Gyan Sunder Shahukhal ◽  
Kiran Babu Tiwari ◽  
Subarna Pokhrel ◽  
Anjana Singh ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Standard Method ◽  
Insecticidal Activity ◽  
Mosquito Larva ◽  
Morphological Characteristics ◽  
Soil Samples ◽  
Insect Bioassay ◽  
Biochemical Tests ◽  
Base Camp ◽  
Microbiological Techniques

Bacillus thuringiensis strains were isolated from soil samples collected from Khumbu Base Camp of the Everest region and characterized by standard microbiological techniques viz. colonial and morphological characteristics, and biochemical tests. Insect bioassay of each isolate was performed by standard method using mosquito larva. Among ten randomly selected isolates, one isolate showed the highest insecticidal activity against Dipteron insects. Keywords: Insect-bioassay, Isolates, Khumbu region, Mosquitocidal, Mosquito larvadoi:10.3126/on.v5i1.800Our Nature (2007)5:67-69

Specificity of action on mosquito larvae of Bacillus thuringiensis israelensis toxins encoded by two different genes

1988 ◽  
Vol 214 (1) ◽  
pp. 42-47 ◽  
Author(s):  
Armelle Delécluse ◽  
Catherine Bourgouin ◽  
André Klier ◽  
Georges Rapoport
Keyword(s):  
Bacillus Thuringiensis ◽  
Mosquito Larvae ◽  
Bacillus Thuringiensis Israelensis
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